Air cooled condenser fan arrangement for control of head pressure in a refrigeration or air conditioning system and method of installing the same



Jan. 24, 1967 l. K

AIR-COOLED CONDENSER FAN ARRANGEMENT FOR CONTROL OF HEAD PRESSURE IN A REFRIGERATION OR AIR CONDITIONING SYSTEM AND METHOD OF INSTALLING THE SAME 3 $heets-$heet 1 A ATTORNEYS 299,650 HEAD I. KRAMER AIR-COOLED CONDENSER FAN ARRANGEMENT FOR CONTROL OF PRESSURE IN A REFRIGERATION OR AIR CONDITIONING SYSTEM AND METHOD OF INSTALLING THE SAME 3 Sheets-Sheet 2 Filed June 4, 1965 INVENTOR I. KRAMER Jan. 24, 1967 PRESSURE IN A REFRIGERATION OR AIR CONDITIONING SYSTEM AND METHOD OF INSTALLING THE SAME 5 Sheets-Sheet 3 Filed June 4, 1965 INVENTOR Ox La L ('Ukn United States Patent Office 3,299,550 Patented Jan. 24, 1967 3,299,650 AIR CUOLED CONDENSER FAN ARRANGEMENT FGR CONTRUL 6F HEAD PRESSURE IN A RE- FREGERATHON GR AIR CONDITEONING SYS- TEM AND ll ilETI-HUD OF INSTALLING THE SAME Israel Kramer, Trenton, NJ assignor to Kramer Trenton Co., Trenton, N..I., a corporation of New Jersey Filed June 4, 1965, er. No. 461,365 12 Claims. (Cl. 62-89) This invention relates to an air cooled condenser fan arrangement for control of head pressure in a refrigeration or air conditioning system and method of installing the same, having for its chief object the provision of an auxiliary fan and motor assembly embodying one or more fans at the face of the condenser opposite to the main fan or fans adapted to supply a relatively small air stream through the condenser, when the main fan or fans is or are stopped to reduce condensing effect on occasions of low ambient temperature, or to increase the effect of the latter when the ambient temperature is high.

Another object is to arrange for control of the actuation of the auxiliary fan motor or motors by the head pressure of the system through a pressure switch, or by the outdoor temperature through the use of a thermostat responsive to ambient temperature in a manner similar to the control of the main fan assembly but so pre-set as to continue rotation of the auxiliary fan or fans during periods of cold ambient temperature when the former is inactive,

Another object is to so position the auxiliary fan and motor assembly that the air stream thereof may be directed against only a portion of the condenser.

Another object is to arrange the condenser and the compressor of the system high side in such mutual relation that the air stream generated by either the main fan assembly and/ or the auxiliary fan assembly follows a course which cools the compressor by blasting the head or heads thereof and bathing the body or bodies after traversing the condenser.

Another object is to provide such an auxiliary fan and motor assembly that may be incorporated in or added to an installed and operating system without the necessity of repiping or alteration, and yet obtain maintenance of the desired predetermined minimum head pressure in the system regardless of outdoor temperature or operating conditions.

Another object is to provide an auxiliary fan any motor assembly that may be so designed as to maintain the minimum head pressure without causing the compressor to cycle due to excessively low head pressure and low crankcase pressure.

Another object is to provide one or more baffle walls or upright shields adjacent the condenser to prevent uncontrolled winds from entering while the main fan or fans are idle and the auxiliary fan assembly is in operation.

Another object is to present a modified arrangement in which the condenser is horizontal with the main fan or fans horizontally above and the auxiliary fan assembly horizontally below the condenser or vice versa.

Another object is to connect the auxiliary fan assembly with the electrical current of the system to operate whenever the compressor is operating, thus establishing in ad Vance the desired minimum head pressure conditions without compressor cycling in conditions of lowest ambient temperature especially when the compressor is starting cold.

A further object is to provide certain improvements in the construction and arrangement of the several parts whereby the above mentioned objects and others inherent in the invention may be efficiently attained.

Practical embodiments of the invention are represented in the accompanying drawings, in which FIG. 1 represents an open somewhat diagrammatic View of the high side of a refrigeration or air conditioning system with an auxiliary fan and motor assembly in operative position;

FIG. 2 represents a similar view, with the compressor removed for remote location;

FIG. 3 represents a view similar to FIG. 2, but showing a taller condenser;

FIG. 4 represents in like manner a modified form or arrangement in which the condenser and compressor are in horizontal relation, with the receiver below the condenser and a Thermobank (See US. Patents Nos. 2,440,146 and 2,718,764 as well as Trademark Registration No. 534,945) below the compressor, together with the addition of a vertical bafile wall positioned to prevent the undesired eifect of wind entering the condenser;

FIG. 5 represents an end elevation of a second modified form or arrangement in which the condenser is horizontally disposed with the main fan or fans above and the auxiliary fan assembly below; and

FIG. 6 represents a view at right angles to FIG. 5.

In brief summary, the invention contemplates the addition to an otherwise normal refrigeration or air conditioning system high side of an auxiliary fan and motor assembly located at the face of the condenser opposite to the face being swept by the main fan or fans, the fan or fans of the said assembly usually being smaller than the main fan or fans and also being designed and adapted principally to generate a relatively small air stream through the condenser when the main fan or fans is or are inactive because of low temperature ambient, thereby maintaining an adequate minimum head pressure for the lowest ambient anticipated at the particular condenser. The auxiliary fan assembly may also be rotated by its motor or motors so as to increase the effect of the main fan or fans during periods of warm ambient; and may be added to an already operating system without the necessity of piping or reconstruction. It should be added that, especially when there is only a single main fan so that there is lack of flexibility in stepwise reduction of the air flow, the provision of more than one auxiliary fan assembly can become desirable in order to achieve stepwise reduction or modulation down to the lowest anticipated ambient temperature at the location of a given installation while still maintaining reasonably satisfactory liquid pressure at the entrance to the thermostatic expansion valve operatively positioned with respect to the inlet of the evaporator. Indeed, the auxiliary fans may be numerous enough and of such size as to add to the condensing capacity during peak warm weather loads; while it is also within the contemplation of this invention to provide, if occasion so dictates, a plurality of auxiliary fans of differing size for stepwise variation or modulation of their functional effect, All of this becomes practical due to the fact that the auxiliary assembly or assemblies, of whatever particular construction, may be operatively attached to previously constructed, and even installed, systems. Again, particularly in instances where the condenser is unusually thick due to a large number of tube stacks, a plurality of sets of motors and fans, or a plurality of fans driven by the same motor, may be arranged on opposite faces of the condenser to move an air stream in the same direction through the condenser in spite of the resistance opposed by its construction. There is further the provision, in a modified form, of a wall like baflle to obstruct the entry of uncontrolled wind into the condenser.

As the condensing capacity of a condenser-fan unit is directly proportional to the condensing temperature minus the temperature of the entering air (commonly referred to as temperature difference or as TD), if it be assumed that a given condenser is sized for a 30 F. TD (i.e. F.

condensing temperature minus 100 F. temperature of the entering air), then a drop in the entering air of 30 F. (i.e. from 100 F. to 70 P.) will cause the condenser to have a condensing capacity twice its original capacity because the TD is now doubled (i.e. 130 F., minus 70 B), so that in this ambient condition the system needs only half of the original condenser. However, while, as noted, the capacity of a condenser is directly proportional to the prevailing TD, its capacity falls only in proportion to the square root of the mas-s air flow (cubic feet per minute), commonly denominated c.f.rn. Thus, it follows that, if a minimum head pressure is to be maintained by reducing the mass air flow through the condenser the reduction will have to be much greater than the percentage increase in TD upon a drop in ambient temperature. For example, in order to counterbalance an increase in TD from 30 F. to 60 F., the c.f.m. would have to be approximately one quarter of the full air flow in the case of a condenser designed with a heat transfer surface of average area; so that to control head pressure by reduction in mass air flow, means must be provided to cause a very radical reduction in the flow which necessarily leads to cumbersome and complicated equipment if only a single fan is used with some modulating means for its air flow, such as dampers. This has led to the employment of a plurality of fans in order that the flow might be modulated in steps by stopping one or more of the fans. I have also considered multiple fans of different air moving ability e.g. three fans of 36", 24", and 16" diameter respectively so that the air flow might he graduated by arresting one or more of the fans, but this is not a satisfactory solution and is not feasible for relatively small size condensing systems.

According to the present invention no special design of condenser is required, as a properly sized auxiliary fan or fans may be combined with an already installed system having one or more of the main fans, a plurality of the latter being conductive to a more gradual reduction in air flow. But when the gradual or stepwise reduction through the sequential stopping of the pluality of main fans is inadequate, the auxiliary fan arrangement of this invention cures the difiiculty and insures the maintenance of the desired minimum head pressure in ambient temperature even much lower than originally anticipated. Further, the auxiliary fan or fans may be calculated in size to meet the lowest temperature encountered in actual experience at the location of any particular system installation, and be added in simple manner as previously explained. And it should be noted that special control means for the auxiliary fan motor or motors is not an essential as the latter may simply be connected with the electrical current of the compressor motor and thus operate the fan or fans whenever the compressor is active to thus establish in advance the desired minimum head pressure and avoid compressor cycling on starting in relatively low ambient temperature.

Turning now to the drawings and referring first to FIG. 1, which shows the high side of an air conditioning system such, for instance, as that of the well known straddle unit in which the system is supported upon a building wall with the low side (evaporator) inside the building and the high side depending against the exterior of the said wall: the said high side comprises a housing consisting of a back 1, top 2, sides, of which one is shown and marked 3, and a front 4 in which is fitted louvers denoted as a whole by 5. As is Well known, these louvers are adjustable, like window shutters, so that they are capable of directing the warm discharged air downwardly to inhibit its tendency to rise and mingle with the cool air stream entering the condenser. An even more effective construction which may be substituted is the so called jiffy hood that is the subject matter of my co-pending application No. 439,146 filed March 12, 1965. The condenser 6 is suitably supported at the upper portion of the front 4, which may be fitted with a grill, or the equivalent, (not illustrated) for the entry of air to the condenser.

The main condenser fan is indicated by 7 and its motor by 8. The compressor 9 is mounted below the condenser upon a horizontal shelf or partition 10 within the housing that may be partial or complete and may leave a chamber or space 11 under it in which is normally located the receiver, Thermobank (see US. Patents Nos. 2,440,146 and 2,718,764, :as well as US. Trademark Registration No. 534,945) if desired, and also a surge tank in some cases, none of these being shown as unnecessary for rep resentation of the present invention. An instrument control panel or box, also not shown, may be fixed either upon or beneath the shelf or partition 10. The hot gas conduit from compressor discharge to condenser is diagrammatically indicated by the line 12 with arrows. The building wall against which the high side hangs, as above explained, is likewise diagrammatically illustrated by a vertical line with slanting projections and bears the general reference numeral 13.

The significant feature of the present invention is, as previously explained, the auxiliary fan 14 with its motor 15, this assembly being supported by a hanger 16 that is suitably fast by any suitable means, such for instance, as bolts, screws or welding, to the upper part 17 of a canopy 18, which may be secured in any suitable manner, as for instance, by bolting or screwing, to the high side housing. The canopy also has slanting sides, one of which is represented in broken lines and marked 19, which sides are fast to or integral with the top 17, to serve the purpose of enclosing the auxiliary fan with its motor, thus constituting a unit readily attachable to the high side housing without disturbing its construction. A circular ring or band 20 surrounds the fan as a guard and director of its air stream, which ring .or band may be fixed in position by any known means of securing it to an adjacent part of the canopy. If desired, the canopy 17, 18, and/or the ring 20 may be omitted as motors of this type [are usually totally enclosed and weatherproof.

It should be emphasized that, as above described, this auxiliary fan unit may be added to a system previously manufactured, and even installed, without any reconstruction of the system, may be sized to suit the particular requirements of each installation, and will adequately perform its function of maintaining the desired predetermined minimum head pressure as previously explained. Likewise, there may be more than one such assembly with one or more fans of appropriate dimension.

The direction of the air stream is indicated by arrows and it will be observed that, after passing through the condenser, it is compelled by the top, sides and back of the high side housing to turn downwardly at an angle of about to blast and cool the hot compressor head, bathe and cool the body thereof, and exit through the downward slanted louvers 5. If the shelf or partition is only partial, so as to be open in part, the air may discharge therethrough.

The showing of FIG. 2 is like that of FIG. 1 except that the compressor is omitted for remote location though, of course, properly connected with the condenser in well known manner, so that the parts shown in this FIG. 2 will be given the same reference numerals as in FIG. 1, and the explanation touching the latter will not be repeated as that would be mere duplication, other than to note that the air stream does not blast and bathe the compressor head and body.

The showing of FIG. 3 corresponds with FIG. 2, with the single difference that the condenser, here marked 21, is nearly twice as tall as that of FIGS. 1 and 2, with the result that the downward flowing air stream traverses the lower portion of the condenser before exiting at the louvers 5. Thus it is deemed unnecessary to add anything further to the above explanations regarding FIGS. 1 and 2, other than to note that, as in FIG. 2, the direction of the air stream may be reversed since the need to blast the head of the compressor is not present.

The modified form of the invention represented in FIG. 4 differs notably from FIGS. 1, 2 and 3 and, consequently, other reference numerals will be applied. This form is well adapted to installation upon a building roof which latter is conventionally indicated by a line marked 22. Here the housing of the high side is horizontally disposed and consists of a top 23, sides, of which one is shown and denoted by 24, and an end 25 fitted with louvers bearing as a general identification the number 26. The opposite end 27 is wholly or largely open and therein is fitted the vertically disposed condenser 28, while a shelf or bottom 29, which may be solid or skeleton, rests upon transversely extending legs 30, 30, that support the whole high side upon the roof 22.

The compressor 31 rests upon the shelf or bottom 29 near the louvers 26, while the main condenser fan 32, with its motor 33, is properly mounted near the condenser and between it and the compressor. Beneath the shelf or bottom 29 and between the legs 30, 30, are located the hereinabove mentioned receiver 34 and Thermobank 35.

The auxiliary fan unit consists, as previously described, of the fan, here identified by 36, its motor 37 supported by the hanger 38 fast to the canopy top 39, the sides, one being shown and indicated by 40, and the suitably fixed fan ring or band 41. This unit is fast at the end 27 of the housing near the upper part of the condenser, as in FIGS. 1, 2 and 3, but it will be clear that the air stream generated by either or both fans flows in a straight horizontal line, as represented by arrows, nevertheless serving to blast the compressor head and bathe its body before emerging from the housing through the louvers 26.

An added feature of this modified form of the invention resides in the vertical bafiie or protective wall 42 uprising from the roof 22 and calculated to shield the condenser from the unwanted entry of uncontrolled wind when the auxiliary fan is alone active and stray uncontrolled winds might upset its effect by causing a further unwanted drop in head pressure due to the added air flow thus produced. It is desirable to locate the baflle 42 a distance from the condenser about equal to the diameter of the fan 32. The duty performed by this bafile can be of notable importance in cases when an uncontrolled wind might cause the auxiliary fan or fans, as well as the main fan or fans, to rotate in a direction opposite to that induced by the motor or motors, similarly to the action of a windmill, with the likelihood of stopping a motor or motors and, possibly, disabling it or them. Also, if desired, an additional bafile may be positioned adjacent the opposite end of the housing for further protection.

A second modified form of the invention is illustrated in FIGS. 5 and 6. As this form differs substantially from the others there will be no repetition of reference numerals in its description.

Here the high side (compressor not shown) is again appropriate for roof mounting. Its housing consists of a front end panel 43 and a similar rear end panel (not shown), together with like side panels, one of which appears and is denoted by 44. This housing is supported by frame members 45 and 46, with the condenser 47 mounted horizontally therein sufliciently elevated to leave a space below it for the auxiliary fan unit held in place by a truncated open or skeleton bracket 48 fast to the mounting 49 for the condenser.

This auxiliary fan unit embodies, as before, a fan 50, its motor 51, and a fan ring or band 52. A pair of main condenser fans are positioned above the condenser, which fans are not shown, as unnecessary, but are merely indicated by fan guards or the like marked 53 and 54. An electrical junction box is represented at 55, while the hot gas inlet for the condenser bears the number 56 and the liquid outlet 57; the compressor being remote and not shown, but, of course, properly connected to the condenser. The lateral projections appearing in FIG. 6,

nection with the previously described figures, there will be no iteration to avoid useless repetition; but it may be desirable to point out that the dififerent forms of the invention adapt themselves to differing demands of various installations.

The performance of the several parts having been fully explained in connection with their constructions, there appears to be no need to set forth the mode or modes of operation; though the valuable contribution of the auxiliary fan unit or units to the automatic maintenance of a predetermined minimum head pressure during low ambient is worthy of emphasis.

I desire it to be understood that various changes may be resorted to in the construction and arrangement of the system elements without departing from the spirit and scope of this invention; and, hence, I do not intend to be limited to details herein shown or described except as they may be included in the claims or be required by disclosures of the prior art.

What I claim is:

1. The combination of a refrigeration or air conditioning system having air cooled condenser with main fan or fans, of at least one auxiliary fan located at the face of the condenser opposite the main fan or fans, and arranged to be operative when the main fan or fans is or are idle during low ambient temperature to supply an air stream adequate to maintain a predetermined minimum head pressure in the system.

2. The combination defined in claim 1, in which combination the auxiliary fan or fans is or are arranged also to be effective during warm ambient temperature or when the condenser is so constructed as to be overly resistant to air flow in order to augment the air stream generated by the main fan or fans.

3. The combination defined in claim 2, in which combination the auxiliary fan or fans is or are adapted to be operatively associated with a previously manufactured system without any reconstruction of the latter.

4. A combination as defined in claim 1, which combination also includes a housing and a compressor with the latter below the condenser, the said housing having an opening below the condenser, and the parts being so arranged that the air stream generated by the fan or fans is directed downwardly by the housing to blast and bathe the compressor and be discharged through the said opening.

5. A combination as defined in claim 4, which combination also includes means positioned at the said opening for inhibiting the discharged air from rising after discharge.

6. A combination as defined in claim 1, in which the condenser, the main fan or fans, and the auxiliary fan or fans are horizontally disposed.

7. A combination as defined in claim 6, in which the main fan or fans is or are above the condenser and the auxiliary fan or fans therebelow.

8. A combination as defined in claim 7, which combination also includes a housing and means for mounting the housing upon a building roof, the last named means being open to permit access of ambient air to the auxiliary fan or fans.

9. A combination as defined in claim 1, which combination also includes a compressor, in which the condenser is vertically disposed and it and the compressor are arranged in horizontal relation so that the fan or fans generates or generate a horizontal air stream.

10. A combination as defined in claim -9, which combination also includes at least one bafiie means disposed to shield the condenser and fan 01: fans from the entry of uncontrolled Wind.

11. A method of installing an air cooled condenser fan arrangement for control of head pressure in a refrigeration or air conditioning system having a main fan or fans which method includes the step of operatively attaching at least one auxiliary fan at the face of the condenser opposite to the main fan or fans.

12. A method as defined in claim 11, which method includes the additional step of providing means for activating the auxiliary fan or fans either when the main fan maintain head pressure in the system, or to augment the air flow when the'main fan or fans is or are operating.

References Cited by the Examiner UNITED STATES PATENTS 1,767,279 6/1930 Bulkeley 230-133 2,148,254 2/1939 Bergstrom 230-133 2,149,107 2/1939 Warren 230-133 2,403,528 7/1946 Higham 62-507 2,655,795 10/1953 Dyer '62183 3,138,941 6/1964 Jensen 62183 3,148,514 9/1964 Mathis 62183 3,152,455 10/1964 Ware 62180 or fans is or are stopped to furnish sufiicient air flow to 5 WILLIAM L WYE, Primary Examiner. 

11. A METHOD OF INSTALLING AN AIR COOLED CONDENSER FAN ARRANGEMENT FOR CONTROL OF HEAD PRESSURE IN A REFRIGERATION OR AIR CONDITIONING SYSTEM HAVING A MAIN FAN OR FANS WHICH METHOD INCLUDES THE STEP OF OPERATIVELY ATTACHING AT LEAST ONE AUXILIARY FAN AT THE FACE OF THE CONDENSER OPPOSITE TO THE MAIN FAN OR FANS. 